Asunto(s)
Huesos/análisis , Minerales/análisis , Partículas Elementales , Métodos , Dispersión de RadiaciónRESUMEN
A new technique was developed for determination of the trabecular bone mineral density in the distal radius. The method is based on measurement of the intensity ratio of coherently and Compton scattered photons using a 241Am radionuclide as the radiation source and a semiconductor crystal as the detector. The bone material consisted of 28 autopsy samples from distal radii of female subjects. A good correlation was observed between bone ash content and the coherent/Compton scattering ratio. The trabecular bone mineral density correlated well with the mineral density values obtained by the gamma transmission method. The method was reproducible within 3%.
Asunto(s)
Minerales/análisis , Radio (Anatomía)/análisis , Dispersión de Radiación , Femenino , Humanos , MétodosRESUMEN
A method based on the measurement of fluorescent and transmitted photons has been developed for the quantitative determination of stable iodine concentrations in tissues. The results are independent of the thickness of the material surrounding the measuring site. The method yields an accuracy of better than 3% for both Ge semiconductor and NaI(TI)detector arrangements.
Asunto(s)
Yodo/análisis , Espectrometría por Rayos X/métodos , Partículas Elementales , Germanio , Humanos , Modelos Anatómicos , Modelos Biológicos , Semiconductores , Yoduro de Sodio , Espectrometría por Rayos X/instrumentación , Distribución TisularRESUMEN
A roentgen ray fluorescence method was developed for the quantitative determination of iodine concentration in tissue. The method is based on the use of two beams, of which one excites the K roentgen rays of iodine, while the other does not. The concentration of iodine was determined from the difference between the counting rates of the fluorescent and the scattered radiation. The measurements were carried out with standard equipment consisting of a generator, a NaI)Tl)-detector and a scaler. An accuracy of 0.1 mg I per g was obtained with the radiation exposure of about 1 R.
Asunto(s)
Yodo/análisis , Espectrometría por Rayos X/métodos , Humanos , Espectrometría por Rayos X/instrumentación , Distribución TisularAsunto(s)
Lípidos/análisis , Hepatopatías/metabolismo , Hígado/análisis , Dispersión de Radiación , Americio , Rayos gamma , HumanosRESUMEN
A new x-ray photographic technique for imaging of small concentrations of iodine in tissues is presented. The method is based on the use of two x-ray beams of slightly different energies, which are obtained from the same primary source by appropriate use of critical absorbers. The beam energies are chosen so that the more energetic one is high enough to excite K x rays of the element under study while the less energetic beam is just below the required excitation energy. Two x-ray pictures are taken using the beams consecutively; thereafter, a difference picture is made by subtracting photographically the lower energy beam picture from that of higher energy. The difference picture then displays the distribution of the element to be imaged. This method is sensitive to iodine concentrations less than 100 microgram/mm2.
Asunto(s)
Yodo/análisis , Fotograbar , Técnica de Sustracción , Rayos XRESUMEN
A new technique for the determination of bone mineral density, based on the detection of both coherently and Compton scattered photons in a narrow beam geometry, is described. Initial results show that this method delivers an accuracy of less than 2% when varying quantities of materials surround the measuring site.
Asunto(s)
Huesos/metabolismo , Densitometría/métodos , Dispersión de Radiación , Humanos , LuzRESUMEN
In this article the background and principles of the intervention and evaluation of the North Karelia Project are presented. The project is a comprehensive community control programme concerning cardiovascular diseases in the province of North Karelia, Eastern Finland. In the baseline survey of the project (1972), 25-59-year-old males had a particularly high of CVD level risk factors; there were 54% current smokers, the mean cholesterol was 269 mg% and the mean casual blood pressure was 147/90 mmHg. According to the myocardial infarction register the incidence rate of acute myocardial infraction was, during the first year of the project (1972), 13.8 per thousand among 30-64-yearold males. During the first 2 1/2 of the intervention the percentage of current smokers decreased among males from 54 to 42. The percentage of males using low-fat milk increased from 17 to 48. The percentage of males who had had their blood pressure measured during the previous half year increased from 28 to 56 and those under antihypertensive drug treatment from 3.1 to 9.1. Local groups for secondary prevention of myocardial infarction were established all over the province. On the basis of the accumulated experience and theoretical considerations, the project plan has futher been elaborated.